I've a dateField in FlexBuilder that returns DateTime from WebService C# and SqlServer.
The dateField show all DateTime from SqlServer, but with Date 'Null', It shows '01/01/1901'
What I need to do to get the datetime instead of null in date field.
You can handle this case on database layer so that all clients of this stored procedure / query will get same default value in case of null.
here's an example:
SELECT name, ISNULL (dateofbirth, GETDATE() ) FROM user
GETDATE() will return today's (server's system) date instead.
of-course not a reasonable default in above example, and you might want to do date manipulations for calculating some default value. you can use these reference docs
I solved problem :
public function IsDateNull(date:Date):String`enter code here`enter code here
{
if (date && date.fullYear == 1901)
{
return null;
}
else
{
return dateTimeFormatter1.format(date);
}
}
<s:DateTimeFormatter id="dateTimeFormatter1"
dateTimePattern="EEEE, dd MMMM , yyyy "
dateStyle="long" locale="it-IT"
errorText="Invalid input value"
useUTC="false"/>
<mx:DateField id="sData_ComunicazioneOSDateField" selectedDate="{classeDati.sData_ComunicazioneOS}" labelFunction="IsDateNull" />
Thank you for the help!!!
Related
I am trying to insert null value from front end. This is my code:
if (!string.IsNullOrEmpty(txtCallTwo.Text))
{
DateTime second = DateTime.ParseExact(txtCallTwo.Text.Trim(), "MM/dd/yyyy", CultureInfo.InvariantCulture);
objclsConsultantLeadStatusProp.dtDate_2nd_Call = second;
}
else
{
DateTime second = DateTime.ParseExact(txtCallTwo.Text.Trim(), "MM/dd/yyyy", CultureInfo.InvariantCulture);
objclsConsultantLeadStatusProp.dtDate_2nd_Call = null;
}
dtDate_2nd_Call property is declared as as Datetime.
You need to make dtDate_2nd_Call as nullable property. Syntax for nullable property is like this.
DateTime? dt = null;
For your case it should be Datetime? dtDate_2nd_Call instead of Datetime dtDate_2nd_Call
The answer to this question is pretty simple. I am not sure if it is of any help to you now...
The DateTime data structure in .NET does not accept null values and thus gives you the error, the simple solution to this is adding a question mark without spaces next to DateTime, i.e., DateTime?
DateTime? data structure accepts null values and thus you won't get the error.
I'm currently working with a client that has a VB.NET web application that was developed internally. They've got everything storing to an Access database which they cannot alter or change for their own reasons. I'm not familiar with any of these technologies, so I'm hoping you may have a solution.
The client has a date field that they are only capturing mm/yyyy or blank. They need this information to save to a datetime field in the database. I'm trying to work up a statement that will automatically take the date entered and convert from mm/yyyy to mm/01/yyyy if the date is provided, or 01/01/1970 if the field was left blank. Can anyone assist?
If we are talking about MS Access functions DateSerial is what you are looking for. The basic syntax is below. If the stored value is text you will need to use the Mid function to parse the text into the year and month and you can use use a hard coded 1 for the day.
DateSerial ( year, month, day )
This function can be used in a select or update. Additional logic will be required to provide a default value for the blank result. Typically in Access this type of logic is done with an IIF.
You can use a combination of the IIf,IsNull and CDate functions, like so:
IIf(IsNull([YourDateFField]),#1/1/1970#,CDate([YourDateFField]))
This tests if your field is null and if yes it returns 1/1/1970, if no it will convert your date string to an actual date (e.g. CDate("04/2014") will return 4/1/2014)
This (MSAccess/VBA) function will do what you are asking. If you pass-in a string like mm/yyyy, it will return a datetime like mm/01/yyyy. However, if the string does not fit that pattern (or equiv), the function will return a date time of 1/1/1970, like you asked.
'in MSAccess:
Public Function mmyyyyToDate(mmyyyy As String) As Datetime
If IsDate(Replace(mmyyyy, "/", "/01/")) Then
Return CDate(Replace(mmyyyy, "/", "/01/"))
Else
Return #1/1/1970#
End If
End Function
It would be more efficient to run it in MSAccess, but if you want to run it in VB.net instead, the syntax is different:
'in VB.NET
Public Function mmyyyyToDate(mmyyyy As Object, Optional defaultDate As DateTime = "1/1/1970") As DateTime
Dim re As DateTime
If Convert.IsDbNull(mmyyyy)
return defaultDate
ElseIf DateTime.TryParse(Replace(mmyyyy, "/", "/01/"), re) Then
Return re
Else
Return defaultDate
End If
End Function
Example of running it:
'MSAccess query syntax
INSERT INTO NewDateTable (NewDateColumn)
SELECT mmyyyyToDate(oldColumn) FROM OldTable
If you can't add a new function to the MSAccess DB, you could turn this function into an inline statement (by using an IIF), but it looks pretty ugly:
'MSAccess query syntax
INSERT INTO NewDateTable (NewDateColumn)
SELECT IIF(IsDate(Replace(oldColumn, "/", "/01/")), Replace(mmyyyy, "/", "/01/"), #1/1/1970#)
FROM OldTable
I have a database with a DateTime column, and want to compare it to some DateTimeOffset. The DateTime column is in (server) local time. There is nothing I can do about that apart from rant about the WTF'yness of it, which I like to do frequently and vehemently, so I can skip it here for now.
I'd like to be able to select all rows from the table where DateTime x happens before my DateTimeOffset. I can live with assuming that if it is DST on the server now, the DateTime column is also in DST and the other way around. These times will be localised around 'now', with the DateTime (almost) always being in the past few hours. I'll take the DST change on the chin when it happens, but the solution shouldn't be always wrong in either DST or non-DST.
As a bonus requirement, the table is large, so performing any manipulation on the DateTime is out of the question. What it comes down to I suppose is I'm looking for the equivalent of
DECLARE #dto datetimeoffset(4) = '12-10-25 12:32:10 +06:00';
DECLARE #dt datetime = --this is where the magic happens?
SELECT * FROM MyTable WHERE datetimecol < #dt
could anyone help me making the magic happen?
You'll need a SQL CLR function to do this. Inspired by this post, I wrote the following:
using System;
using Microsoft.SqlServer.Server;
public class UserDefinedFunctions
{
[SqlFunction(IsDeterministic = false)]
public static DateTime? ConvertDateTimeOffsetToLocalDateTime(DateTimeOffset? dto)
{
if (!dto.HasValue)
return null;
return dto.Value.ToLocalTime().DateTime;
}
}
You can compile this yourself if you like, or just deploy it using the following, which contains the serialized binary and SQL deployment script:
EXEC sp_configure 'clr enabled', 1;
GO
RECONFIGURE
GO
CREATE ASSEMBLY [SqlClrDateTime]
FROM 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WITH PERMISSION_SET = SAFE
GO
CREATE FUNCTION dbo.ConvertDateTimeOffsetToLocalDateTime(#dto datetimeoffset)
RETURNS datetime2
AS EXTERNAL NAME SqlClrDateTime.UserDefinedFunctions.ConvertDateTimeOffsetToLocalDateTime
GO
And here is how you can use it in your scenario:
DECLARE #dto datetimeoffset(4) = '12-10-25 12:32:10 +06:00'
DECLARE #dt datetime = dbo.ConvertDateTimeOffsetToLocalDateTime(#dto)
SELECT * FROM MyTable WHERE datetimecol < #dt
if i have the following to access an sql database for a date to compare it to a string that a user enters:
public IQueryable<Audit> FindAllAuditsByNameDate(String name, String date)
{
return from audit in db.Audits
where audit.EventTime.ToString().Contains(date) && audit.User.UserName.Contains(name)
orderby audit.User.UserName
select audit;
}
it fails is the user enters the "/" character in a date. how do i work around this?
Try DateTime.Parse. It's able to understand a lot of the common formats for entering DateTimes.
DateTime dateStart = DateTime.Parse(date);
DateTime dateEnd = dateStart.AddDays(1);
return from audit in db.Audits
where audit.EventTime >= dateStart &&
audit.EventTime < dateEnd &&
audit.User.UserName.Contains(name)
orderby audit.User.UserName
select audit;
If DateTime.Parse doesn't parse the format you want, you can always use DateTime.ParseExact and provide your own format strings.
Considering EventTime is of type DateTime? you need to check it against its value. First convert the string date to DateTime
DateTime newDate = Convert.ToDateTime(date);
return from audit in db.Audits
where audit.EventTime.Value == newDate && audit.User.UserName.Contains(name)
orderby audit.User.UserName
select audit;
Warning - Don't use Contains.
Disadvantages of Contains
Suppose I have two list objects.
List 1 List 2
1 12
2 7
3 8
4 98
5 9
6 10
7 6
Using Contains, it will search for each List-1 item in List-2 that means iteration will happen 49 times !!!
Answer to your original Question
public IQueryable<Audit> FindAllAuditsByNameDate(String name, String date)
{
DateTime Dt;
if (DateTime.TryParse(date, out Dt))
{
return from audit in db.Audits
where audit.EventTime.ToString().Contains(date) && audit.User.UserName.Contains(name)
orderby audit.User.UserName
select audit;
}
return null;
}
TryParse
Returns a bool indicating whether it succeeded.
It just try/catch internally that why is implemented without exceptions so that it is fast.
Use it in case the value may be InValid.
Parse
Throws an exception.
Use it if you are sure the value will be valid
I have a stored procedure which updates a database using the parameters I supply but I'm having trouble passing a NULL to the stored procedure
The field I need to make NULL is a DateTime field
DB.Parameters.AddWithValue("#date", NULL)
This gives me the error
'NULL' is not declared. 'Null' constant is no longer supported; use 'System.DBNull' instead
So I tried
DB.Parameters.AddWithValue("#date", DBNull.Value.ToString())
But this produces the value 1900-01-01 00:00:00.000 in the column as it's passing a "" to the field
I also tried
DB.Parameters.AddWithValue("#date", DBNull.Value)
But it produces this error
Value of type 'System.DBNull' cannot be converted to 'String'.
Has anybody got any ideas?
Or you can add your parameter like this, which gives it a null value in the database if your variable is null:
DB.Parameters.AddWithValue("#date", myDateTime ?? (object)DBNull.Value);
you need to set it as a nullable type as Amit mentioned.
More details and background available at http://evonet.com.au/overview-of-c-nullable-types/
Try something like this, using Add rather than AddWithValue:
DB.Parameters.Add("#date", SqlDbType.DateTime).Value = DBNull.Value;
Try this
If you are using class and its property and those property values are used as parameter then you can do this
chnage the signature of the property to
public DateTime? myDateTime = null;// Here ? is used to make the property nullable.
Also if your date column is of type varchar then correct it to Date (Sql2008) / DateTime(2005).
//change parameter to this
#SomeDate datetime = null (as suggested by chris)
Allow the field to accept null and then pass the value as
DB.Parameters.Add("#date", DBNull.Value)
This is an example. It's work for me
if(obj.myDate == DateTime.MinValue)
{
aCommand.Parameters.Add("dateParameter", SqlDbType.Date).Value = DBNull.Value;
}
else
{
aCommand.Parameters.Add("dateParameter", SqlDbType.Date).Value = obj.myDate ;
}